utlStreamHelper: FIFOStream.Clear added

uutlStreamHelper.pas

@@ -120,6 +120,7 @@ type
     function Seek(const {%H-}Offset: Int64; {%H-}Origin: TSeekOrigin): Int64; override; overload;
     procedure BeginOperation;
     procedure EndOperation;
+    procedure Clear;
     property LockFree: boolean read fLockFree;
   end;
 
@@ -479,23 +480,9 @@ begin
 end;
 
 destructor TutlFIFOStream.Destroy;
-var
-  p,q: PPage;
 begin
-  BeginOperation;
-  try
-    fTotalSize:= 0;
-    fReadPtr:= 0;
-    fWritePtr:= 0;
-    p:= fPageFirst;
-    while p<>nil do begin
-      q:= p;
-      p:= p^.Next;
-      Dispose(q);
-    end;
-  finally
-    EndOperation;
-  end;
+  Clear;
+  Dispose(fPageFirst);
   FreeAndNil(fDataLock);
   inherited Destroy;
 end;
@@ -627,6 +614,25 @@ begin
     fDataLock.Release;
 end;
 
+procedure TutlFIFOStream.Clear;
+var
+  p: PPage;
+begin
+  BeginOperation;
+  try
+    while fPageFirst<>fPageLast do begin
+      p:= fPageFirst;
+      fPageFirst:= fPageFirst^.Next;
+      Dispose(p);
+    end;
+    fTotalSize:= 0;
+    fReadPtr:= 0;
+    fWritePtr:= 0;
+  finally
+    EndOperation;
+  end;
+end;
+
 { TutlBase64Decoder }
 
 function TutlBase64Decoder.{%H-}Read(var Buffer; Count: Longint): Longint;